Dr Jingxian Yu

Dr Jingxian Yu completed his BEng (Applied Chemistry) and MSc (Physical Chemistry) degrees in China, and PhD (nanoscience & nanotechnology) in Australia. Upon the completion of his PhD program he moved to the University of Cambridge, UK as a Roger Pysden Research Fellow and later the University of Nottingham, UK as a postdoctoral research fellow. He returned to Australia in 2009 to take up an ARC Australian Postdoctoral Fellowship (APD Fellow) at the University of Adelaide. Currently, he is a Senior Research Fellow & Senior Lecturer at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) headed by the University of Adelaide. He has a specific interest in electron transfer in peptides using combined electrochemical and computational techniques, and a growing interest in biological applications of nanomaterials. He is a recipient of a number of awards, including the CASS Foundation Award, Roger Pysden Memorial Fellowship, Ian Potter Foundation Award, Flinders University Overseas Travelling Fellowship and AMY Forwood Travelling Award.

Bio-inspired molecular electronics

Electron transfer in proteins can occur over long molecular distances to facilitate a number of crucial biological processes, including respiration and photosynthesis. A fundamental understanding of electron transfer in proteins is not only central to the elucidation of these essential biological processes in living organisms, but also to the design and development of bio-inspired molecular electronic components. Much research has been conducted on charge transfer in proteins, including azurin and the mitochondrial electron carrier, cytochrome C. However, in light of the complexity of such systems, synthetic model peptides present as excellent alternatives. Such peptides can adopt specific secondary structures, for instance helices and β-strands through diligent design, to allow the study of electron transfer in a somewhat more controlled setting. Furthermore, specific functionalization of their backbone enables precision-branching, a key feature of three-dimensional molecular circuitry. While molecular electronics provides an opportunity to begin to redefine integrated circuit technologies, one must first understand and subsequently be able to predict and control the associated charge transfer kinetics and dynamics before this vision can be realized.

A direct link between backbone rigidity and electron transfer provides a novel approach for the development of switchable molecular components.

To address these questions, we use a combination of theory and experiment to advance a fundamental understanding of electron transport in naturally occurring peptides, while exploiting their electronic properties to promote the design and development of functional bio-inspired molecular electronic devices. A bottom-up approach for the fabrication of components for the electronics industry will be required in the not too distant future, with the combination of solid-state techniques used here closely aligning to future device development.

Biological applications of nanomaterials

The controlled transport of molecules across membranes is central to nature (e.g., in protein channels and ion pumps) but also to many highly valuable applications such as desalination, on-demand drug delivery, chromatography, and others. Artificial nanoporous membranes, for example nanoporous anodic alumina membranes (NAAMs), provide an important tool for studying the mechanisms and dynamics associated with molecular transporting across a membrane.

(a) Typical SEM image of nanoporous anodic alumina membranes (NAAMs); (b) Photo-regulated gatekeeper when the PSP-NAAM is exposed to the light of different wavelengths; (c) Molecular transport of dye through PSP-NAAM after alternative exposure to 440 and 364 nm light.

Here, an alternative approach to overcome the inherent limitations of polymer-based stimuli-responsive membranes, while providing the practical and functional requirements for selective on-demand molecular transport applications, are synthetic nanoporous membranes modified with optically switchable molecules (PSP-NAAMs). The results showed that the molecular transport across PSP-NAAMs could be repeatedly switched between on and off state, which is highly significant for on-demand triggered drug release systems.